Field of the Invention
This disclosure relates to the generation of power through a multi-step process: 1) biological conversion and removal of sulfur from fecal matter as well as other biologically digestible materials containing sulfur and carbon, i.e., biomining, and 2) oxidizing the reduced sulfur in an oxygen/sulfur electrolytic flow cell arrangement. The spent sulfur is recirculated back into the biominer for recycling.
Description of the Related Art
The generation of power electrochemically is most commonly related to a fuel cell device where gaseous hydrogen and oxygen are fed into an electrolytic cell device. Sometimes hydrocarbons are feed to the system and are reformed into hydrogen for use in the generation device. Hydrogen is an expensive fuel source because it is typically used for manufacturing of higher value chemicals and not on low value fuel. A fuel cell uses catalysts to help the oxidation and reduction reactions. These cells have an efficiency limit because of internal resistance of the materials and geometries used. Fuel cells are found in low and high temperature designs. Each style has benefits and drawbacks.
Some sulfur based power generation technology (USPTO 2011/0226631A1) discussed using elemental sulfur electrodes in an electrolytic cell to generate power. The attempt was to consume sulfur currently being disposed of from other industrial processes in a process to generate supplemental power. The system uses organic electrolyte and the anode is consumable. Another method was found to generate power from sulfur dissolving in a solvent in a reaction cell used for high precision detection equipment (U.S. Pat. No. 4,169,779). This method was for analytical use only and would definitely not be feasible for power generation at any scale. Finally, two other processes were found in professional journals that simply tried to oxidize sulfide only to elemental sulfur for removal from solution as a particulate. While this process is of no direct interest, their abstract describes the lengths that most sewage treatment systems will go to abate sulfide formation indicating that given the correct food sources this production is spontaneous. (J Environ Manage Feb. 1, 2015; 149:263-70. Doi: 10.1016/j.jenvman 2014.10.024 Epub Nov. 15, 2014 ) (Water Res 2008 December: 42(20):4965-75. Doi:10.106/j.watres.2008.09.007 Epub Sep. 27, 2008 )
Other forms of electrolytic devices for power production normally are found in storage and rechargeable batteries. In these various technologies are found many parings of oxidation and reduction reactants, electrolytes and electrode configurations. Many of the current designs use lithium, a low weight to power ratio material as a reactant.
One other attempt at generating power using bacterial conversion of waste organics grew bacteria directly on electrodes and does demonstrate power generation. This technology appears to only be viable in lab environments due to at least one issue; the bacteria is in an environment where it can grow unchecked and would clog the operating components.